continuous cms gc. even though it is not hitting CMSInitiatingOccupancyFraction=68 Is thsi a know issue
Y Srinivas Ramakrishna
Y.S.Ramakrishna at Sun.COM
Mon Nov 26 23:14:53 UTC 2007
Hi Thomas --
We'll fix this conflation/confusion in the "next" release; i filed:
CR 6634032 CMS: Need CMSInitiatingOccupancyPermFraction for perm, divorcing from CMSInitiatingOccupancyFraction
thanks.
-- ramki
----- Original Message -----
From: Thomas Viessmann <Thomas.Viessmann at Sun.COM>
Date: Monday, November 26, 2007 10:29 am
Subject: Re: continuous cms gc. even though it is not hitting CMSInitiatingOccupancyFraction=68 Is thsi a know issue
To: hotspot-gc-dev at openjdk.java.net
> Hi Ramki,
>
>
> IMO permspace collection should not be triggered by the CMS threshold
> at
> all.
> Or at least not before it's 90% full. Otherwise, if the CMS threshhold
>
> was relatively
> low, Permspace would have to be wasted. A problem in particular for 32
> bit
> applications.
>
> Thomas
>
>
> Y Srinivas Ramakrishna schrieb:
> > Hi Anuj --
> >
> > the reason is that perm gen collection is enabled and the occupancy
> of
> > the perm gen has exceeded the triggering threshold. (The criterion currently
> > is to start the collection if either perm gen or old gen occupancy
> exceeds the threshold.)
> > A workaround might be to increase MaxPermSize. The JVM should clearly
> > be more "ergonomic" about this, but even otherwise it might be desirable
> > (what do people feel?) to somehow divorce the two thresholds (which
> are
> > currently conflated as one).
> >
> > -- ramki.
> >
> > ----- Original Message -----
> > From: Anuj Lal <alal at hotwire.com>
> > Date: Wednesday, November 21, 2007 2:27 pm
> > Subject: continuous cms gc. even though it is not hitting
> CMSInitiatingOccupancyFraction=68 Is thsi a know issue
> > To: hotspot-gc-dev at openjdk.java.net
> > Cc: hotspotgc-feedback at sun.com
> >
> >
> >
> >> We just moved to 1.5.0.13 from 1.4.12. It sin production.
> >>
> >> I am opening sun support case too.
> >>
> >>
> >>
> >> -Xms2460m -server
> >>
> >> -XX:+UseConcMarkSweepGC
> >>
> >> -XX:+UseParNewGC
> >>
> >> -XX:+CMSParallelRemarkEnabled
> >>
> >> -XX:+UseCMSCompactAtFullCollection
> >>
> >> -XX:CMSFullGCsBeforeCompaction=0
> >>
> >> -XX:+HandlePromotionFailure
> >>
> >> -XX:CMSInitiatingOccupancyFraction=68
> >>
> >> -XX:+UseCMSInitiatingOccupancyOnly
> >>
> >> -Xmx2460m
> >>
> >> -XX:NewSize=462M
> >>
> >> -XX:MaxNewSize=462M
> >>
> >> -XX:MaxTenuringThreshold=5
> >>
> >> -XX:SurvivorRatio=5
> >>
> >> -XX:TargetSurvivorRatio=80
> >>
> >> -XX:PermSize=256M
> >>
> >> -XX:MaxPermSize=256M
> >>
> >> -XX:-DisableExplicitGC
> >>
> >> -XX:+CMSPermGenSweepingEnabled
> >>
> >> -XX:+CMSClassUnloadingEnabled
> >>
> >> -XX:CMSMaxAbortablePrecleanTime=1
> >>
> >>
> >>
> >>
> >>
> >> Here I sthe snippet of log. See used is only used 599703K an jvm keep
> >> doing cms gc
> >>
> >>
> >>
> >> Anuj
> >>
> >>
> >>
> >>
> >>
> >> concurrent mark-sweep generation total 2045952K, used 599703K
> >> [0x6b600000, 0xe8400000, 0xe8400000)
> >>
> >> concurrent-mark-sweep perm gen total 262144K, used 182700K [0xe8400000,
> >> 0xf8400000, 0xf8400000)
> >>
> >> 474868.841: [ParNew
> >>
> >> Desired survivor size 55364812 bytes, new threshold 5 (max 5)
> >>
> >> - age 1: 11103424 bytes, 11103424 total
> >>
> >> - age 2: 4182448 bytes, 15285872 total
> >>
> >> - age 3: 6066672 bytes, 21352544 total
> >>
> >> - age 4: 7075376 bytes, 28427920 total
> >>
> >> : 363413K->27933K(405504K), 0.1678588 secs]
> >> 963116K->627636K(2451456K)Heap after gc invocations=22744:
> >>
> >> par new generation total 405504K, used 27933K [0x4e800000,
> >> 0x6b600000, 0x6b600000)
> >>
> >> eden space 337920K, 0% used [0x4e800000, 0x4e800000, 0x63200000)
> >>
> >> from space 67584K, 41% used [0x67400000, 0x68f47550, 0x6b600000)
> >>
> >> to space 67584K, 0% used [0x63200000, 0x63200000, 0x67400000)
> >>
> >> concurrent mark-sweep generation total 2045952K, used 599703K
> >> [0x6b600000, 0xe8400000, 0xe8400000)
> >>
> >> concurrent-mark-sweep perm gen total 262144K, used 182700K [0xe8400000,
> >> 0xf8400000, 0xf8400000)
> >>
> >> }
> >>
> >> , 0.1688079 secs]
> >>
> >> 474869.011: [GC [1 CMS-initial-mark: 599703K(2045952K)]
> >> 628140K(2451456K), 0.1199002 secs]
> >>
> >> 474869.132: [CMS-concurrent-mark-start]
> >>
> >> 474876.273: [CMS-concurrent-mark: 7.004/7.141 secs]
> >>
> >> 474876.273: [CMS-concurrent-preclean-start]
> >>
> >> 474876.344: [CMS-concurrent-preclean: 0.069/0.071 secs]
> >>
> >> 474876.344: [CMS-concurrent-abortable-preclean-start]
> >>
> >> CMS: abort preclean due to time 474877.846:
> >> [CMS-concurrent-abortable-preclean: 1.006/1.502 secs]
> >>
> >> 474877.854: [GC[YG occupancy: 211030 K (405504 K)]474877.854: [Rescan
> >> (parallel) , 0.6154592 secs]474878.470: [weak refs processing,
> >>
> >> 0.3838744 secs]474878.854: [class unloading, 0.1124973 secs]474878.966:
> >> [scrub symbol & string tables, 0.0976109 secs] [1 CMS-remar
> >>
> >> k: 599703K(2045952K)] 810733K(2451456K), 1.2858288 secs]
> >>
> >> 474879.150: [CMS-concurrent-sweep-start]
> >>
> >> 474882.602: [CMS-concurrent-sweep: 3.336/3.452 secs]
> >>
> >> 474882.602: [CMS-concurrent-reset-start]
> >>
> >> 474882.846: [CMS-concurrent-reset: 0.244/0.244 secs]
> >>
> >> 474882.985: [GC [1 CMS-initial-mark: 595574K(2045952K)]
> >> 897595K(2451456K), 1.2062837 secs]
> >>
> >> 474884.192: [CMS-concurrent-mark-start]
> >>
> >> 474889.371: [CMS-concurrent-mark: 5.179/5.179 secs]
> >>
> >> 474889.371: [CMS-concurrent-preclean-start]
> >>
> >> 474889.459: [CMS-concurrent-preclean: 0.084/0.088 secs]
> >>
> >> 474889.459: [CMS-concurrent-abortable-preclean-start]
> >>
> >> CMS: abort preclean due to time 474891.671:
> >> [CMS-concurrent-abortable-preclean: 1.004/2.212 secs]
> >>
> >> 474891.799: [GC[YG occupancy: 330467 K (405504 K)]474891.799: [Rescan
> >> (parallel) , 1.0003167 secs]474892.800: [weak refs processing,
> >>
> >> 0.4521800 secs]474893.252: [class unloading, 0.1199606 secs]474893.372:
> >> [scrub symbol & string tables, 0.1051379 secs] [1 CMS-remar
> >>
> >> k: 595574K(2045952K)] 926042K(2451456K), 1.7586947 secs]
> >>
> >> 474893.562: [CMS-concurrent-sweep-start]
> >>
> >> 474895.970: [CMS-concurrent-sweep: 2.408/2.408 secs]
> >>
> >> 474895.970: [CMS-concurrent-reset-start]
> >>
> >> 474896.187: [CMS-concurrent-reset: 0.217/0.217 secs]
> >>
> >> 474898.296: [GC [1 CMS-initial-mark: 594417K(2045952K)]
> >> 932649K(2451456K), 1.2541899 secs]
> >>
> >> 474899.551: [CMS-concurrent-mark-start]
> >>
> >> 474904.513: [CMS-concurrent-mark: 4.962/4.962 secs]
> >>
> >> 474904.513: [CMS-concurrent-preclean-start]
> >>
> >> 474904.584: [CMS-concurrent-preclean: 0.068/0.071 secs]
> >>
> >> 474904.584: [CMS-concurrent-abortable-preclean-start]
> >>
> >> CMS: abort preclean due to time 474906.523:
> >> [CMS-concurrent-abortable-preclean: 1.017/1.938 secs]
> >>
> >> 474906.549: [GC[YG occupancy: 346194 K (405504 K)]474906.549: [Rescan
> >> (parallel) , 1.0806458 secs]474907.630: [weak refs processing,
> >>
> >> 0.4560526 secs]474908.086: [class unloading, 0.1184826 secs]474908.205:
> >> [scrub symbol & string tables, 0.0981007 secs] [1 CMS-remar
> >>
> >> k: 594417K(2045952K)] 940611K(2451456K), 1.8293189 secs]
> >>
> >> 474908.379: [CMS-concurrent-sweep-start]
> >>
> >> 474910.636: [CMS-concurrent-sweep: 2.256/2.256 secs]
> >>
> >> 474910.636: [CMS-concurrent-reset-start]
> >>
> >> 474910.782: [CMS-concurrent-reset: 0.146/0.146 secs]
> >>
> >> 474912.320: [GC [1 CMS-initial-mark: 594402K(2045952K)]
> >> 949362K(2451456K), 1.2208158 secs]
> >>
> >> 474913.542: [CMS-concurrent-mark-start]
> >>
> >> 474914.002: [GC {Heap before gc invocations=22744:
> >>
> >> par new generation total 405504K, used 365853K [0x4e800000,
> >> 0x6b600000, 0x6b600000)
> >>
> >> eden space 337920K, 100% used [0x4e800000, 0x63200000, 0x63200000)
> >>
> >> from space 67584K, 41% used [0x67400000, 0x68f47550, 0x6b600000)
> >>
> >> to space 67584K, 0% used [0x63200000, 0x63200000, 0x67400000)
> >>
> >>
>
>
> --
>
> ---
> mit freundlichen Gruessen / with kind regards
>
>
> Thomas Viessmann
>
> Global Sales and Services - Software Support Engineering
>
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